#include<stdio.h>
#include<ctype.h>
#include<string.h>
struct order
{
    char productName[52];
    int productID;
    float price;
};
int isValidName(char name[]){
    for (int i=0;name[i] !='\0';i++)
    {
        if(!isalnum(name[i]))
        {
            return 0;
        }
        return 1;
    }
}
int main()
{
    int n;
    scanf("%d",&n);
    if(n<0)
    {
        printf("Invalid input");
        return 0;
    }
    struct Order orders[10];
    float total=0;
    for(!isvalidName(orders[i].productName))
    {
        printf("Invalid input\n");
        return 0;
    }
    total+=orders[i].price;
}
printf("%.2f\n",total);